Recently, biological molecule detecting methods, in which physicians or technicians detect biological molecules at points of care, immediately obtain measurement results, and utilize the measurement results for diagnosis and treatment, are being focused on. Biological molecule detecting methods are methods for selectively detecting only detection target substances from within bodily fluids such as blood, urine, and sweat, by the high selectivity of specific reactions such as antigen antibody reactions. Such biological molecule detecting methods are particularly widely employed to detect, inspect, quantify, and analyze small amounts of biological molecules, such as viruses, nucleic acids, proteins, and germs.
Radioimmunoassay is a biological molecule detecting method which is in practical use. Radioimmunoassay employs antigens or antibodies labeled with isotopes, and detects the presence of antibodies or antigens that specifically bind with the labeled antigens or the labeled antibodies.
Fluorescence immunoassay is a biological molecule detecting method that does not employ radioactive substances. Fluorescence immunoassay apparatuses, in which antibodies are immobilized onto a reaction layer in advance (referred to as a solid phase), a measurement target solution and antibodies labeled with fluorescent molecules are caused to flow onto the reaction layer, and fluorescence in the vicinity of the reaction layer is observed to measure the concentration of antigens which have specifically bound to the antibodies, are known (refer to Japanese Unexamined Patent Publication No. 7 (1995)-120397, for example).
However, fluorescence immunoassay that utilizes solid phases has a problem that it is costly to produce the solid phases. There is a method that utilizes fluorescence polarization method to confirm antigen antibody reactions in solutions (referred to as a liquid phase) as a method that does not employ solid phases. The fluorescence polarization method is a method that detects changes in degrees of fluorescence polarization caused by changes in Brownian motion that occurs by the sizes of molecules changing by molecules binding with molecules which have fluorescent labels. The biological molecule detecting method that utilizes the fluorescence polarization method is known as a simple and expedient method for detecting detection target substances within samples (refer to Japanese Unexamined Patent Publication No. 2008-298743, for example).